Method and apparatus for generating a 2D panoramic image

Abstract

The present invention proposes a method for producing a 2D panoramic image of an oral cavity comprising the steps: A) provision of a plurality of projection images acquired during an at least partial revolution of a recording unit comprising a radiation source and an electronic image sensor about the oral cavity in a given position; B) calculation of an image including at least one anatomical feature from the plurality of projection images using a calculation rule with reconstruction parameters; C) provision of a model of the at least one anatomical feature, which describes the at least one anatomical feature in a target position in an image; D) identification of the at least one anatomical feature in the calculated image; E) determination of a deviation between an actual position of the at least one identified anatomical feature in the calculated image and the target position of the at least one anatomical feature in the model by applying a metric; F) variation of at least one of the reconstruction parameters and recalculation of at least one part of the image that shows the at least one anatomical feature using the calculation rule and the at least partially varied reconstruction parameters or variation of a pixel transformation and application of the pixel transformation to at least one part of the calculated image that shows the at least one anatomical feature, so that at least this part of the image is recalculated; G) derivation of the 2D panoramic image from the recalculated image; and H) outputting the 2D panoramic image.

The invention claimed is: 
     
       1. Method for generating a 2D panoramic image of an oral cavity comprising the steps
 A) Provision of a plurality of projection images acquired during an at least partial revolution of a recording unit comprising a radiation source and an electronic image sensor about the oral cavity in a given position, 
 B) Calculation of an image including at least one anatomical feature from the plurality of projection images using a calculation rule with reconstruction parameters, 
 C) Provision of a model of the at least one anatomical feature, which describes the at least one anatomical feature in a target position in an image, 
 D) Identification of the at least one anatomical feature in the calculated image, 
 E) Determination of a deviation between an actual position of the at least one identified anatomical feature in the calculated image and the target position of the at least one anatomical feature in the model by applying a metric, 
 F) Variation of at least one of the reconstruction parameters and recalculation of at least one part of the image that shows the at least one anatomical feature using the calculation rule and the at least partially varied reconstruction parameters or variation of a pixel transformation and application of the pixel transformation to at least one part of the calculated image that shows the at least one anatomical feature, so that at least this part of the image is recalculated, 
 F-1) Redetermination of the deviation between the actual position of the at least one identified anatomical feature in the calculated image and the target position of the at least one anatomical feature in the model by applying a metric, 
 G) Derivation of the 2D panoramic image frons the recalculated image; and 
 H) Outputting the 2D panoramic image. 
 
     
     
       2. Method according to  claim 1 , wherein after Step F-1) and before Step G) the method comprises the following steps:
 F-2) Repetition of Steps F) and F-1) until the determined deviation is less than a specified threshold value and 
 F-3) if the entire image was not recalculated in Step F-1), recalculation of at least one part of the image that was not yet recalculated in Step F) using the at least partially varied reconstruction parameters or applying the at least one pixel transformation to at least one part of the image that was not yet recalculated in Step F). 
 
     
     
       3. Method according to  claim 1 , wherein the provision of the plurality of projection images in step A) includes an acquisition of the plurality of projection images during an at least partial revolution of the recording unit about the oral cavity. 
     
     
       4. Method according to  claim 1 , wherein the calculation rule is designed such that the variation of the at least one reconstruction parameter in Step F) leaves at least one further imaging property, different from the position of the oral cavity, of the 2D panoramic image displayed in Step H) substantially unchanged. 
     
     
       5. Method according to  claim 4 , wherein, when varying the at least one reconstruction parameter, an effect of said at least one reconstruction parameter on the at least one further imaging property is substantially compensated in Step F). 
     
     
       6. Method according to  claim 4 , wherein the at least one further imaging property of the 2D panoramic image displayed in step H) is selected from a position of a layer that is sharply imaged in the 2D panoramic image, a radiation penetration angle and a thickness of the imaged layer. 
     
     
       7. Method according to  claim 1 , wherein a plurality of reconstruction parameters are varied in Step F), sc that, in addition to the position of the oral cavity, a further imaging property different from the position of the oral cavity changes, wherein the calculation rule is designed such that the position of the oral cavity and the further imaging property are changed independently of one another. 
     
     
       8. Method according to  claim 1 , wherein the at least one anatomical feature is selected from a position and or shape of a tooth, a temporomandibular joint, a palate, at least one element of the spine, a collarbone and/or a bone. 
     
     
       9. Method according to  claim 1 , wherein the at least one anatomical feature comprises anatomical symmetry. 
     
     
       10. Method according to  claim 1 , wherein the model describes the anatomical feature in the form of a 2D description or a 3D description. 
     
     
       11. Method according to  claim 1 , wherein:
 in Step D), at least one anatomical feature is identified in a first section and at least one anatomical feature is identified in a second section of the calculated image, in Step E), deviation between the at least one anatomical feature identified in the first section and the model, and a deviation between the at least one anatomical feature identified in the second section and the model, are determined by applying a metric, 
 in Step F), at least one reconstruction parameter for the first section and at least one reconstruction parameter for the second section of the calculated image are varied separately from one another, 
 in Step F-1), a deviation between the at least one identified anatomical feature in the first section and the model, and a deviation between the at least one identified anatomical feature in the second section and the model, are again determined by applying a metric, and 
 in Step J), Steps F) and F-1) are repeated until the respective determined deviations are less than a specified threshold value. 
 
     
     
       12. Method according to  claim 11 , wherein the first section of the calculated image is an upper section, which includes at least parts of the upper jaw, and the second section of the calculated image is a lower section, which includes at least parts of the lower jaw. 
     
     
       13. Method according to  claim 1 , wherein the method for collecting a change in the position of the oral cavity is used during a revolution of the recording unit, wherein the first section and the second section of the calculated image are arranged directly or indirectly adjacent to one another in a revolution direction of the recording unit. 
     
     
       14. An Method according to  claim 1 , wherein a measure for the variation of the at least one reconstruction parameter, preferably with a specification of a direction, an amount and/or a type of variation is provided along with the 2D panoramic image in Step H). 
     
     
       15. Apparatus for generating a 2D panoramic image of an oral cavity comprising:
 a recording unit having a radiation source and an electronic image sensor,
 wherein the recording unit is configured and designed such that a plurality of projection images can be acquired during an at least partial revolution of the recording unit about the oral cavity in a given position, 
 
 and a computer, 
 wherein the computer is operatively connected to the image sensor such that
 said computer receives the plurality of projection images from the image sensor, and 
 
 wherein the computer is configured such that the computer executes the steps 
 A) Receiving the plurality of projection images from the recording unit, 
 B) Calculation of an image including at least one anatomical feature from the plurality of projection images using a calculation rule with reconstruction parameters, 
 C) Provision of a model of the at least one anatomical feature, which describes the at least one anatomical feature in a target position in an image, 
 D) Identification of the at least one anatomical feature in the calculated image, 
 E) Determination of a deviation between an actual position of the at least one identified anatomical feature in the calculated image and the target position of the at least one anatomical feature in the model by applying a metric, 
 F) Variation of at least one of the reconstruction parameters and recalculation of at least one part of the image that shows the at least one anatomical feature using the calculation rule and the at least partially varied reconstruction parameters or 
 Variation of a pixel transformation and application of the pixel transformation to at least one part of the calculated image that shows the at least one anatomical feature, so that at least this part of the image is recalculated, 
 F-1) Redetermination of the deviation between the actual position of the at least one identified anatomical feature in the calculated image and the target position of the at least one anatomical feature in the model by applying a metric, 
 G) Derivation of the 2D panoramic image from the recalculated image; and 
 H) Outputting the 2D panoramic image.